I totally hear you and there may be a few of us interested in joining you I suspect but many unseen hurdles will present themselves. Even now just off the dome
What app type shall be built (twitter etc)
How much functionality will we have at that time (such as a easy way to search a DB)
What price will maid be and will people feel comfortable parting with them if price is steadily rising?
How high of a cost or barrier to develop said app?
So many questions indeed.
Something as simple as secure chat on mobile or a mobile wallet will most likely be easily built or ported so could be a lot of competition.